rator initial temperature, then the cool down test has
been failed and further A/C system diagnosis is
required. If the test is failed, the snowflake icon and
the DELAY text will continue to blink across ignition
cycles until the vehicle has been driven for greater
than 13 km (8 miles).
A/C PERFORMANCE TEST
The A/C system is designed to remove heat and
humidity from the air entering the passenger com-
partment. The evaporator, located in the HVAC hous-
ing, is cooled to temperatures near the freezing point.
As warm damp air passes over the fins in the A/C
evaporator, moisture in the air condenses to water,
dehumidifying the air. Condensation on the evapora-
tor fins reduces the evaporators ability to absorb
heat. During periods of high heat and humidity, an
A/C system will be less effective. With the instru-
ment control set to recirculation mode, only air from
the passenger compartment passes through the A/C
evaporator. As the passenger compartment air dehu-
midifies, A/C performance levels rise.
Humidity has an important bearing on the temper-
ature of the air delivered to the interior of the vehi-
cle. It is important to understand the effect that
humidity has on the performance of the A/C system.
When humidity is high, the A/C evaporator has to
perform a double duty. It must lower the air temper-
ature, and it must lower the temperature of the
moisture in the air that condenses on the evaporator
fins. Condensing the moisture in the air transfers
heat energy into the evaporator fins and tubing. This
reduces the amount of heat the A/C evaporator can
absorb from the air. High humidity greatly reduces
the ability of the A/C evaporator to lower the temper-
ature of the air.
However, evaporator capacity used to reduce the
amount of moisture in the air is not wasted. Wring-
ing some of the moisture out of the air entering the
vehicle adds to the comfort of the passengers.
Although, an owner may expect too much from their
A/C system on humid days. A performance test is the
best way to determine whether the system is per-
forming up to design standards. This test also pro-
vides valuable clues as to the possible cause of
trouble with the A/C system. The ambient air tem-perature in the location where the vehicle will be
tested must be a minimum of 21É C (70É F) for this
test.
PERFORMANCE TEST PROCEDURE
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - WARNING - A/C PLUMBING) and (Refer to
24 - HEATING & AIR CONDITIONING/PLUMBING -
FRONT - CAUTION - A/C PLUMBING).
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer and a manifold gauge
set.
(2) Set the mode control to the Recirculation Mode
position, the temperature control to the full cool posi-
tion and the blower to the highest speed position.
(3) Start the engine and hold at 1,000 rpm with
the A/C compressor clutch engaged.
(4) The engine should be warmed up to operating
temperature with the doors closed and windows
open.
(5) Insert a thermometer in the driver's side center
panel A/C-heater outlet and operate the engine for
five minutes.
(6) If the compressor clutch does not engage, pro-
ceed with diagnosis of the compressor clutch coil.
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS - FRONT/COMPRESSOR CLUTCH
COIL - DIAGNOSIS AND TESTING).
(7) With the A/C compressor clutch engaged, com-
pare the air temperature at the center panel outlet
and the compressor discharge pressure to the A/C
Performance Temperature and Pressure chart. The
compressor clutch may cycle, depending upon the
ambient temperature and humidity. If the clutch
cycles, use the readings obtained before the clutch
disengaged.
RSHEATING & AIR CONDITIONING24-7
HEATING & AIR CONDITIONING (Continued)
A/C PERFORMANCE TEMPERATURE AND PRESSURE
Ambient
Temperature21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Left Center Panel
Outlet Discharge
Air Temperature1to8ÉC
(34 to 46É F)3to9ÉC
(37 to 49É F)4 to 10ÉC
(39 to 50É F)6to11ÉC
(43 to 52É F)7 to 18É C
(45 to 65É F)
Discharge
Pressure (High
Side Service Port)1034 to 1724
kPa
(150 to 250 psi)1517 to 2275
kPa
(220 to 330 psi)1999 to 2620
kPa
(290 to 380 psi)2068 to 2965
kPa
(300 to 430 psi)2275 to 3421
kPa
(330 to 450 psi)
Suction Pressure
(Low Side Service
Port)103 to 207 kPa
(15 to 30 psi)117 to 221 kPa
(17 to 32 psi)138 to 241 kPa
(20 to 35 psi)172 to 269 kPa
(25 to 39 psi)207 to 345 kPa
(30 to 50 psi)
(8) If the air outlet temperature fails to meet the
specifications in the A/C Performance Temperature
and Pressure chart, or if the compressor discharge
pressure is high, refer to the A/C Pressure Diagnosis
Chart.
A/C PRESSURE DIAGNOSIS
Condition Possible Causes Correction
Rapid A/C compressor clutch
cycling (ten or more cycles
per minute).1. Low refrigerant system
charge.1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
Equal pressures, but the
compressor clutch does not
engage.1. No refrigerant in the
refrigerant system.1. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
2. Faulty fuse. 2. Check the fuses in the Integrated Power
Module. Repair the shorted circuit or component
and replace the fuses, if required. Refer to Group
8.
3. Faulty A/C compressor
clutch coil.3. See A/C Compressor Clutch Coil in this group.
Test the compressor clutch coil and replace, if
required.
4. Faulty A/C compressor
clutch relay.4. See A/C Compressor Clutch Relay in this
group. Test the compressor clutch relay and relay
circuits. Repair the circuits or replace the relay, if
required.
5. Improperly installed or
faulty evaporator temperature
sensor.5. See Evaporator Temperature Sensor in this
group. Test the sensor and replace, if required.
6. Faulty A/C pressure
transducer.6. See A/C Pressure Transducer in this group.
Test the sensor and replace, if required.
7. Faulty Powertrain Control
Module (PCM).7. Refer to the proper Diagnostic Procedures
manual for testing of the PCM. Test the PCM and
replace, if required.
24 - 8 HEATING & AIR CONDITIONINGRS
HEATING & AIR CONDITIONING (Continued)
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control panel, the following could require
service:
²Blend door binding.
²Faulty blend door actuator.
²Faulty A/C-heater control.
²Faulty related wiring harness or connectors.²Improper engine coolant temperature.
SPECIFICATIONS
A/C SYSTEM
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood Specifica-
tion Label.
SYSTEM SPECIFICATIONS
Item Description Notes
A/C Compressor Denso 10S17 ± 2.4L/2.5L/2.8L/3.3L
without rear A/C
Denso 10S20 ± 3.3L/3.8L with rear
A/CND-8 PAG Oil
Freeze±up Control Evaporator temperature sensor HVAC housing mounted (RS models),
Evaporator mounted (RG models) - input to
A/C-heater control module
Low PSI Control A/C pressure transducer Liquid line mounted - input to Powertrain Control
Module (PCM) - PCM opens compressor clutch
relay above 200 kPa (29 psi)
High PSI Control A/C pressure transducer Liquid line mounted - input to PCM - PCM
opens compressor clutch relay below 3100 kPa
(450 psi)
High Pressure relief valve Compressor mounted - opens above 3445-4135
kPa (500-600 psi), closes below 2756 kPa (400
psi)
Compressor Clutch Coil
DrawDenso 10S17 ± 3.3 amps @ 12V
0.5V @ 21É C (70É F)
Denso 10S20 ± 2.2 amps @ 12V
0.5V @ 21É C (70É F)
Compressor Clutch Air
Gap0.35 - 0.60 mm (0.014 - 0.024 in.)
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A/C Compressor Shaft Bolt 17.5 ± 155
A/C Compressor Mounting Bolts (2.4L/2.5L/2.8L) 28 21 ±
A/C Compressor Mounting Bolts (3.3L/3.8L) 54 40 ±
A/C Compressor Mounting Bracket Bolts (2.4L) 54 40 ±
A/C Condenser Mounting Bracket Screws 5 ± 45
A/C Expansion Valve Screws 11 ± 97
A/C-Heater Control Screws 2 ± 17
Blend Door Actuator Screws 2 ± 17
Blower Motor Screws 2 ± 17
Blower Motor Power Module Screws (ATC) 2 ± 17
Blower Motor Resistor Block Screws (MTC) 2 ± 17
Center Bezel Outlet Screws 2 ± 17
RSHEATING & AIR CONDITIONING24-11
HEATING & AIR CONDITIONING (Continued)
CONTROLS - FRONT
TABLE OF CONTENTS
page page
A/C COMPRESSOR CLUTCH/COIL
DESCRIPTION.........................13
OPERATION...........................13
DIAGNOSIS AND TESTING
A/C COMPRESSOR CLUTCH COIL........14
STANDARD PROCEDURE
CLUTCH INSPECTION.................15
A/C CLUTCH BREAK-IN................15
REMOVAL.............................15
INSTALLATION.........................16
A/C COMPRESSOR CLUTCH RELAY
DESCRIPTION.........................18
OPERATION...........................18
REMOVAL.............................19
INSTALLATION.........................19
A/C HEATER CONTROL
DESCRIPTION.........................19
STANDARD PROCEDURE
A/C-HEATER CONTROL CALIBRATION.....19
REMOVAL.............................20
INSTALLATION.........................20
A/C PRESSURE TRANSDUCER
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING
A/C PRESSURE TRANSDUCER..........21
REMOVAL.............................21
INSTALLATION.........................21
BLEND DOOR ACTUATOR
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................22
BLOWER MOTOR RELAY
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................24INSTALLATION.........................24
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION.........................24
OPERATION...........................24
DIAGNOSIS AND TESTING
FRONT BLOWER MOTOR RESISTOR
BLOCK.............................25
REMOVAL.............................25
INSTALLATION.........................25
EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................26
OPERATION...........................27
REMOVAL
RG MODELS.........................27
RS MODELS.........................27
INSTALLATION
RG MODELS.........................27
RS MODELS.........................28
INFRARED TEMPERATURE SENSOR
DESCRIPTION.........................28
OPERATION...........................28
MODE DOOR ACTUATOR
DESCRIPTION.........................29
OPERATION...........................29
REMOVAL.............................29
INSTALLATION.........................30
POWER MODULE - BLOWER MOTOR
DESCRIPTION.........................30
OPERATION...........................30
REMOVAL.............................30
INSTALLATION.........................31
RECIRCULATION DOOR ACTUATOR
DESCRIPTION.........................31
OPERATION...........................31
REMOVAL.............................32
INSTALLATION.........................32
A/C COMPRESSOR CLUTCH/
COIL
DESCRIPTION
The A/C compressor clutch assembly consists of a
stationary electromagnetic A/C clutch field coil with a
zener diode, a pulley bearing and pulley assembly,
and a clutch plate (Fig. 1). These components provide
the means to engage and disengage the A/C compres-
sor from the engine accessory drive belt.The A/C clutch field coil and the pulley bearing
and pulley assembly are both retained on the nose of
the A/C compressor with snap rings. The clutch plate
is splined to the compressor shaft and secured with a
bolt.
OPERATION
The compressor clutch components provide the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
RSCONTROLS - FRONT24-13
clutch plate into contact with the clutch pulley and
drives the compressor shaft. When the coil is not
energized, the pulley freewheels on the clutch hub
bearing, which is part of the pulley.
A zener diode is connected in parallel with the
clutch electromagnetic coil. This diode controls the
dissipation of voltage induced into the coil windings
by the collapsing of the electromagnetic fields that
occurs when the compressor clutch is disengaged.
The zener diode dissipates this induced voltage by
regulating a current path to ground. This arrange-
ment serves to protect other circuits and components
from potentially damaging voltage spikes in the vehi-
cle electrical system that might occur if the voltage
induced in the clutch coil windings could not be dis-
sipated.
The compressor clutch engagement is controlled by
several components: the heater-A/C controls in the
passenger compartment, the A/C pressure transducer
on the liquid line, the evaporator temperature sensor
on the expansion valve for automatic temperature
control (ATC) system or on the HVAC housing for
manual temperature control (MTC) system, the Pow-
ertrain Control Module (PCM) in the engine compart-
ment, and the compressor clutch relay in the
Integrated Power Module (IPM). The PCM may delay
compressor clutch engagement for up to thirty sec-
onds (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL
MODULE - DESCRIPTION - PCM OPERATION).
DIAGNOSIS AND TESTING
A/C COMPRESSOR CLUTCH COIL
The air conditioning compressor clutch coil electri-
cal circuit is controlled by the powertrain control
module (PCM) through the A/C compressor clutch
relay, which is located in the integrated power mod-
ule (IPM) in the engine compartment. Begin testing
of a suspected compressor clutch coil problem by per-
forming the preliminary checks.
PRELIMINARY CHECKS
(1) If the compressor clutch will not engage, verify
the refrigerant charge level (Refer to 24 - HEATING
& AIR CONDITIONING/PLUMBING - FRONT/RE-
FRIGERANT - DIAGNOSIS AND TESTING -
REFRIGERANT CHARGE LEVEL). If the refriger-
ant charge level is OK, go to Step 2. If the refriger-
ant charge level is not OK, adjust the refrigerant
charge as required.
(2) If the A/C compressor clutch still will not
engage, disconnect the wire harness connector for the
A/C pressure transducer and check for battery cur-
rent at the connector with the engine running and
the A/C-heater control set to the A/C mode. If OK, go
to TESTS. If not OK, refer to Body Diagnostic Proce-
dures to perform further diagnosis.
TESTS
(1) Verify the battery state of charge (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
(2) Connect an ammeter (0 to 10 ampere scale
selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.
(3) With the heater-A/C control in the A/C mode
and the blower at low speed, start the engine and
allow it to run at a normal idle speed.
(4) The compressor clutch should engage immedi-
ately, and the clutch coil voltage should be within
two volts of the battery voltage. If the coil voltage is
not within two volts of battery voltage, test the
clutch coil feed circuit for excessive voltage drop. If
the compressor clutch does not engage, refer to Body
Diagnostic Procedures to perform further diagnosis.
(5) For the acceptable A/C clutch coil current draw
specificationsrefer to 24 - HEATING & AIR CONDI-
TIONING - SPECIFICATIONS. Specifications apply
for a work area temperature of 21É C (70É F). If volt-
age is more than 12.5 volts, add electrical loads by
turning on electrical accessories until voltage reads
below 12.5 volts.
(a) If the compressor clutch coil current reading
is zero, the coil is open and must be replaced.
Fig. 1 A/C Compressor Clutch
1 - BOLT
2 - CLUTCH PLATE
3 - PULLEY AND BEARING
4 - FIELD COIL
5 - SNAP RING (2)
6 - SHIM
24 - 14 CONTROLS - FRONTRS
A/C COMPRESSOR CLUTCH/COIL (Continued)
(b) If the compressor clutch coil current reading
is four amperes or more, the coil is shorted and
must be replaced.
STANDARD PROCEDURE
CLUTCH INSPECTION
NOTE: The compressor clutch can be serviced in
the vehicle. The refrigerant system can remain fully-
charged during compressor clutch, pulley, or coil
replacement.
Examine the friction surfaces of the clutch pulley
and the clutch plate for wear. The pulley and plate
should be replaced if there is excessive wear or scor-
ing.
If the friction surfaces are oily, inspect the shaft
and nose area of the A/C compressor for refrigerant
oil. If refrigerant oil is found, the compressor shaft
seal is leaking and the A/C compressor must be
replaced.
Check the clutch pulley bearing for roughness or
excessive leakage of grease. Replace the pulley and
bearing assembly, if required.
A/C CLUTCH BREAK-IN
After a new A/C compressor clutch has been
installed, cycle the compressor clutch approximately
twenty times (five seconds on, then five seconds off).
During this procedure, set the A/C-heater controls to
the A/C Recirculation Mode, the blower motor in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces of the compressor
clutch, which provides optimum compressor clutch
torque capability.
REMOVAL
NOTE: The compressor clutch can be serviced in
the vehicle. The refrigerant system can remain fully-
charged during compressor clutch, pulley, or coil
replacement.
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(3) Raise and support the vehicle.
(4) Disconnect the engine wire harness connector
for the compressor clutch coil from the clutch coil pig-
tail wire connector on the top of the A/C compressor.
(5) On models with the 3.3L and 3.8L engines, dis-
engage the retainer on the engine wire harness com-pressor clutch coil take out from the bracket on the
top of the A/C compressor.
(6) On models with the 2.4L, 2.5L and 2.8L
engines, remove all of the compressor mounting bolts
except the upper left (rear of the A/C compressor),
which should only be loosened. Allow the front (pul-
ley end) of the A/C compressor to tilt downward far
enough to access the clutch for removal, then tighten
the loosened upper left compressor mounting bolt.
(7) On models with the 3.3L and 3.8L engines,
remove the two bolts and two nuts that secure the
A/C compressor to the engine. Disengage the mount-
ing ear at the front of the A/C compressor from the
stud on the engine, allow the front (pulley end) of the
A/C compressor to tilt downward far enough to access
the clutch for removal, then reinstall and tighten the
upper left compressor mounting bolt.
(8) Remove the compressor shaft bolt (Fig. 2). A
band-type oil filter wrench or a strap wrench may be
used to secure the clutch during bolt removal.
(9) Tap the clutch plate lightly with a plastic mal-
let to release it from the splines on the compressor
shaft. Remove the clutch plate and shim(s) from the
compressor shaft (Fig. 3).
NOTE: Use care not to lose any of the shim(s).
Fig. 2 A/C Compressor Shaft Bolt
1 - BOLT
2 - COMPRESSOR CLUTCH PLATE
RSCONTROLS - FRONT24-15
A/C COMPRESSOR CLUTCH/COIL (Continued)
CAUTION: Do not pry between the clutch plate unit
and the pulley to remove the clutch plate from the
compressor shaft as this may damage the clutch
plate.
(10) Using snap ring pliers (Special Tool C-4574 or
equivalent), remove the external snap ring that
secures the pulley to the front cover of the A/C com-
pressor, then slide the pulley off of the compressor
(Fig. 4).
(11) Remove the screw that secures the clutch coil
pigtail wire connector bracket and ground clip to the
top of the compressor housing.
(12) Using snap ring pliers (Special Tool C-4574 or
equivalent), remove the external snap ring that
secures the clutch coil to the front cover of the com-
pressor housing, then slide the clutch coil off of the
A/C compressor (Fig. 5).
INSTALLATION
(1) Align the dowel pin on the back of the clutch
coil with the hole in the compressor front cover and
position the clutch coil onto the A/C compressor. Be
certain that the clutch coil pigtail wires are properly
oriented and routed so that they are not pinched
between the compressor front cover and the clutch
coil.
NOTE: A new snap ring must be used to secure the
clutch coil to the A/C compressor. The bevel side of
the snap ring must face outward.(2) Using snap ring pliers (Special Tool C-4574 or
equivalent), install the external snap ring that
secures the clutch coil to the front cover of the A/C
Fig. 3 Clutch Plate and Shim(s)
1 - COMPRESSOR SHAFT
2 - CLUCH PLATE
3 - SHIM
Fig. 4 Clutch Pulley Snap Ring
1 - SNAP RING
2 - SNAP RING PLIERS
3 - CLUTCH PULLEY AND BEARING
Fig. 5 Remove Clutch Coil Snap Ring
1 - SNAP RING PLIERS
2 - CLUTCH COIL
3 - COMPRESSOR
4 - SNAP RING
24 - 16 CONTROLS - FRONTRS
A/C COMPRESSOR CLUTCH/COIL (Continued)
compressor. The bevel side of the snap ring must face
outward and both snap ring eyelets must be oriented
to the right or the left of the clutch coil dowel pin
location on the A/C compressor. Be certain that the
snap ring is fully and properly seated in the groove.
CAUTION: If the snap ring is not fully seated in the
groove it will vibrate out, resulting in a clutch fail-
ure and severe damage to the compressor front
cover.
(3) Install and securely tighten the screw that
secures the clutch coil pigtail wire connector bracket
and ground clip to the top of the compressor housing.
(4) Install the pulley onto the front cover of the
A/C compressor. If necessary, tap the pulley gently
with a block of wood placed on the pulley friction sur-
face (Fig. 6).
CAUTION: Do not mar the friction surfaces of the
pulley.
NOTE: A new snap ring must be used to secure the
clutch pulley to the A/C compressor. The bevel side
of the snap ring must face outward.
(5) Using snap ring pliers (Special Tool C-4574 or
equivalent), install the external snap ring (bevel side
facing outward) that secures the clutch pulley to the
front cover of the A/C compressor. Be certain that the
snap ring is fully and properly seated in the groove.(6) If the original clutch plate and clutch pulley
are to be reused, reinstall the original shim(s) on the
compressor shaft against the shoulder. If a new
clutch plate and/or clutch pulley are being used,
install a trial stack of shims 2.54 mm (0.010 in.)
thick on the compressor shaft against the shoulder.
(7) Install the clutch plate onto the compressor
shaft.
NOTE: The shims may compress after tightening
the shaft bolt. Check the air gap in four or more
places to verify the air gap is still correct. Spin the
pulley before performing a final check of the air
gap.
(8) With the clutch plate assembly tight against
the shim(s), measure the air gap between the clutch
plate and the pulley face with feeler gauges. The air
gap should be between 0.35 - 0.60 mm (0.014 - 0.024
in.). If the proper air gap is not obtained, add or sub-
tract shims as needed until the desired air gap is
obtained.
(9) Install the compressor shaft bolt. Tighten the
bolt to 17.5 N´m (155 in. lbs.).
(10) On models with the 2.4L, 2.5L and 2.8L
engines, loosely install the four bolts that secure the
A/C compressor to the mounting bracket on the
engine (2.4L), or the cylinder block (2.5L/2.8L).
Tighten the bolts to 28 N´m (21 ft. lbs.).
(11) On models with the 3.3L and 3.8L engines,
loosely install the two bolts and two nuts that secure
the A/C compressor to the engine. Tighten each of the
fasteners to 54 N´m (40 ft. lbs.) using the following
sequence:
²The upper nut at the front of the compressor.
²The lower nut at the front of the compressor.
²The upper bolt at the rear of the compressor.
²The lower bolt at the rear of the compressor.
(12) On models with the 3.3L and 3.8L engines,
engage the retainer on the engine wire harness com-
pressor clutch coil take out with the bracket on the
top of the A/C compressor.
(13) Connect the engine wire harness connector to
the A/C compressor clutch coil.
(14) Install the accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
INSTALLATION).
(15) Lower the vehicle.
(16) Reconnect the negative battery cable.
Fig. 6 Clutch Pulley - Installation
1 - PULLEY AND BEARING
2 - WOOD BLOCK
RSCONTROLS - FRONT24-17
A/C COMPRESSOR CLUTCH/COIL (Continued)